SYNTHESIS OF 12-METAL CLUSTERS BASED ON THE [MO6CL8]4- X-RAY STRUCTURE OF (PPN)2[MO6CL(I)8((MU-NC)MN(CO)2CP)(A)6( CORE )

Reaction of (Bu4N)2[Mo6Cli8(CF3SO3)a6] With [CpMn(CO)2CN]-, [CpMn(CO)( NO)CN], or [CpRu(PPh3)2CN] leads to replacement of all six CF3SO3- ani ons by the organometallic ligands, which are attached through the ambi dent CN- ligand. The unusual decrease in nu(CN) upon complex formation appears to arise from increased M-C back-pi-bonding and, in one case where it can be assessed, reduced kinematic coupling. A very strong el ectronic absorption band for these complexes is attributed to mixing o f charge transfer with localized transitions. Crystallographic data fo r (PPN)2[Mo6Cli8{mu-NC)Mn(CO)2Cp}a6]: triclinic space group, P1 (No. 2 ), a = 17.803-(6) angstrom, b = 19.082(2) angstrom, c = 29.787(6) angs trom, alpha = 73.45(1)degrees, beta = 85.00(2)degrees, gamma = 72.38(2 )degrees, V = 9245(7) angstrom3, Z = 3.